Identification of specific markers for airway cells is an important prerequisite in studies of the development and differentiation of pulmonary airway cells. We plan to identify non-serum proteins in lung lavage and raise monoclonal antibodies to the proteins. The antibodies will be tested for their reactivity to and specificity for airway cells by immunocytochemistry. Availability of markers specific of different airway cells will facilitate the study of development of the cells. Cell specific markers will be used to study the effect of a number of factors on the development of airway cells, using morphology, immunocytochemistry, morphometry and quantitation of proteins as the methologic approaches. Studies of the regulation of development of airway epithelium may be important in the treatment of patients with bronchopulmonary dysplasia. Identification and structural analyses of the cell specific proteins is also likely to provide insight into the function of different airway cells. Knowledge of the function of specific proteins of airway cells may provide clues to the pathogenesis of chronic obstructive pulmonary disease and emphysema. We will isolate cell specific proteins, and plan to examine their amino acid sequence and, in the long run, isolate the genes for the proteins. Availability of cDNA probes for the genes will be valuable in studies of gene regulation of the airway cell specific proteins.